Carlo A. Gerboni

Implementation and validation of a 6 degrees-of-freedom nonlinear helicopter model

The paper describes the implementation and validation of a nonlinear model of the UH-60 helicopter. The implemented model is based on a physical vehicle and includes various important subsystems in order to increase the model fidelity. The validation is carried out through a Handling Qualities (HQ) evaluation and a comparison with flight data. Various standardized tests have been performed in the time and frequency domain for hover and the forward flight condition. Results obtained have been analyzed according to the criteria defined by the Aeronautical Design Standard ADS-33E-PRF. The behavior of our helicopter model is very similar to flight test data of the UH-60 in hover and in forward flight, although some coupling effects are not well described. Overall the model provides a reliable basis for use in motion-base simulators and as framework for conducting studies on control augmentation systems.

Control augmentation strategies for helicopters used as personal aerial vehicles in low-speed regime

In this paper an augmentation strategy is implemented with the goal of making the behavior of an actual helicopter similar to that of a new class of aerial systems called Personal Aerial Vehicles (PAVs). PAVs are meant to be flown by flight-naive pilots, i.e., pilots with minimal flight experience. One feature required for achieving this goal, is to have a Translation Rate Command (TRC) response type in the hover and low-speed regime. In this paper, a TRC response type is obtained for a UH-60 helicopter simulation model in hover and low-speed regime through the implementation of nonlinear backstepping control. The responses of the rotorcraft with TRC response type are evaluated with the metrics defined in the Aeronautical Design Standard ADS-33E-PRF. Simulations show the efficiency of the control scheme in tracking the reference velocities and the achievement of the requirements to have level 1 Handling Qualities (HQ) for the TRC response type.

Variable force-stiffness haptic feedback for learning a disturbance rejection task

This paper investigates the use of a variable haptic feedback for training a disturbance rejection task. The haptic feedback was designed as a Force-Stiffness feedback. Throughout the training, Force and Stiffness feedback are decreased to progressively give more control authority to the human operator. The training method was tested in a human-in-the-loop experiment. In the experiment, participants were split into three groups: variable haptic aid (VHA), constant haptic aid (CHA) and no haptic aid (NoHA). The VHA and CHA groups performed a first training phase with variable and constant haptic feedback respectively, followed by an evaluation phase without external aids. The NoHA group performed the entire experiment without external aids. Results showed that in the training phase both VHA and CHA groups performed better than NoHA group. In the evaluation phase though, only the VHA group obtained better performances than the NoHA group. Specifically, participants were able to quickly recover similar performances to those obtained at the end of the training phase. Thus, the variable haptic training proved to be more effective than the constant haptic training and manual control at helping participants learn the task.